Soy formulas are commonly used for infants in the united states. Recent studies have shown that a component of soy formula, phytic acid, reduces mineral absorption from these products. It is now possible to produce soy formula with dephytinized soy protein isolate. In addition, partially hydrolyzed dephytinized soy isolate is available, which may also improve protein digestibility of these products. In this study, infant rhesus monkeys were fed from birth either regular soy formula or soy formula that had been dephytinized or both dephytinized and hydrolyzed formula. Infants were followed for 4 months and weight drawn monthly. The results show that zinc status was lower in infants fed regular soy formula than in the other groups. Copper status, however, was lower in dephytinized formula, but not in the dephytinized/hydrolyzed product. These results suggest that dephytinization and hydrolysis of proteins in soy formula improves trace element status of infants.